The present invention is directed toward a shipping box lockdown arrangement and more particularly toward an improved shipping box which can be utilized with a conventional lockdown device but which increases shipping capacity.
It is well known to ship large containers on cargo airplanes and particularly military airplanes. In order to prevent movement of the shipping boxes both laterally and vertically, lockdown devices are provided on such planes which interfit with a portion of the shipping box.
Conventional lockdown devices for military cargo transport are comprised of a pair of elongated hinged metal plates secured to the floor of the aircraft. The hinged plates are arranged parallel to each other but spaced apart a sufficient distance to allow the shipping box to be positioned between the two plates with the side walls of the box being essentially parallel to the plates. Extending outwardly from the bottom of the box and perpendicular to the side walls thereof are a pair of flat rails, each of which includes a plurality of spaced apart tabs and a plurality of openings between the tabs. After the shipping box is in place between the hinged locking members, the locking members are pivoted from their inoperative position wherein they lie away from the rails to their operative position where they over lie the rails. Each locking member includes a substantially continuous plate which lies over the tabs to hold the shipping box down and a plurality of projections that extend into the openings between the tabs to prevent lateral movement of the shipping box. A lock can then be applied to the locking members to prevent them from being pivoted into their inoperative position until the same is desired.
The locking members are permanently secured to the floor of the aircraft and cannot be moved closer to or further away from each other. Thus, heretofore, only standard and uniform shipping boxes could be employed. That is, the width of the shipping box was limited by the fact that the lockdown rails extending outwardly from the bottom of the side walls thereof had to fit precisely between the elongated spaced apart hinged locking members so that they could properly engage the rails. A wider shipping box, therefore, could not be employed since the hold down rails on the box would then not properly interact with the locking members. This has somewhat limited the size of shipping boxes that could be carried on cargo aircraft.